Supercooling apparatus

ABSTRACT

The present invention relates to a supercooling apparatus which can reduce a deviation of energy applied to a stored object. The supercooling apparatus includes a storage room provided in a storing unit where the cooling is performed and having a storing space therein to store or receive an object, a heat source supply unit installed in the storage room and supplying heat to the storing space or generating heat in the storing space; a temperature sensing unit sensing the temperature of the storing space or the stored object, and a control unit operating the heat source supply unit based on the temperature sensed by the temperature sensing unit to enable an upper portion of the storing space to have a temperature higher than a temperature of the maximum ice crystal formation zone, such that the storing space or the stored object is maintained in a supercooled state at a temperature below the maximum ice crystal formation zone, the control unit supplying or generating heat over a given magnitude during the supercooled-state control.

TECHNICAL FIELD

The present invention relates to a supercooling apparatus, and, more particularly, to a supercooling apparatus which can reduce a deviation of energy applied to a stored or received object during the cooling.

BACKGROUND ART

Supercooling means the phenomenon that a molten object or a solid is not changed although it is cooled to a temperature below the phase transition temperature in an equilibrium state. A material has a stable state at every temperature. If the temperature is slowly changed, the constituent elements of the material can follow the temperature changes, maintaining the stable state at each temperature. However, if the temperature is suddenly changed, since the constituent elements cannot be changed to the stable state at each temperature, the constituent elements maintain a stable state of the initial temperature, or some of the constituent elements fail to be changed to a state of the final temperature.

For example, when water is slowly cooled, it is not temporarily frozen at a temperature below 0° C. However, when water enters a supercooled state, it has a kind of quasi-stable state. As this unstable equilibrium state is easily broken even by slight stimulation, water tends to move to a more stable state. That is, if a small piece of material is put into the supercooled liquid, or if the liquid is suddenly shaken, the liquid starts to be frozen at once such that its temperature reaches the freezing point, and maintains a stable equilibrium state at this temperature.

In general, an electrostatic atmosphere is made in a refrigerator and meat and fish are thawed in the refrigerator at a minus temperature. In addition to the meat and fish, fruit is kept fresh in the refrigerator.

This technology uses a supercooling phenomenon. The supercooling phenomenon indicates the phenomenon that a molten object or a solid is not changed although it is cooled to a temperature below the phase transition temperature in an equilibrium state.

This technology includes Korean Patent Publication No. 2000-0011081 titled “Electrostatic field processing method, electrostatic field processing apparatus, and electrodes therefor”.

FIG. 1 is a view of an example of a conventional thawing and freshness-keeping apparatus. A keeping-cool room 1 is composed of a thermal insulation material 2 and an outer wall 5. A mechanism (not shown) controlling a temperature inside the room 1 is installed therein. A metal shelf 7 installed in the room 1 has a two-layer structure. Target objects to be thawed or freshness-kept and ripened such as vegetables, meat and marine products are loaded on the respective layers. The metal shelf 7 is insulated from the bottom of the room 1 by an insulator 9. In addition, since a high voltage generator 3 can generate 0 to 5000 V of DC and AC voltages, an insulation plate 2 a such as vinyl chloride, etc. is covered on the inside of the thermal insulation material 2. A high-voltage cable 4 outputting the voltage of the high voltage generator 3 is connected to the metal shelf 7 after passing through the outer wall 5 and the thermal insulation material 2.

When a user opens a door installed at the front of the keeping-cool room 1, a safety switch 13 (see FIG. 2) is turned off to intercept the output of the high voltage generator 3.

FIG. 2 is a circuit view of the circuit configuration of the high voltage generator 3. 100 V of AC is supplied to a primary side of a voltage regulation transformer 15. Reference numeral 11 represents a power lamp and 19 a working state lamp. When the door 6 is closed and the safety switch 13 is on, a relay 14 is operated. This state is displayed by a relay operation lamp 12. Relay contact points 14 a, 14 b and 14 c are closed by the operation of the relay 14, and 100 V of AC is applied to the primary side of the voltage regulation transformer 15.

The applied voltage is regulated by a regulation knob 15 a on a secondary side of the voltage regulation transformer 15, and the regulated voltage value is displayed on a voltmeter. The regulation knob 15 a is connected to a primary side of a boosting transformer 17 on the secondary side of the voltage regulation transformer 15. The boosting transformer 17 boosts the voltage at a ratio of 1:50. For example, when 60 V of voltage is applied, it is boosted to 3000 V.

One end O₁ of the output of the secondary side of the boosting transformer 17 is connected to the metal shelf 7 insulated from the keeping-cool room 1 through the high-voltage cable 4, and the other end O₂ of the output is grounded. Moreover, since the outer wall 5 is grounded, if the user touches the outer wall 5 of the keeping-cool room 1, he/she does not get an electric shock. Further, in FIG. 1, when the metal shelf 7 is exposed in the room 1, it should be maintained in an insulated state in the room 1. Thus, the metal shelf 7 needs to be separated from the wall of the room 1 (the air performs an insulation function). Furthermore, if a target object 8 is protruded from the metal shelf 7 and brought into contact with the wall of the room 1, the current flows to the ground through the wall of the room 1. Therefore, the insulation plate 2 a is attached to the inner wall to prevent drop of the applied voltage. Still furthermore, when the metal shelf 7 is covered with vinyl chloride without being exposed in the room 1, an electric field atmosphere is produced in the entire room 1. In the prior art, an electric field or a magnetic field is applied to the stored object to be cooled, such that the stored object enters a supercooled state. Accordingly, a complicated apparatus for producing the electric field or the magnetic field should be provided to keep the stored object in the supercooled state, and the power consumption is increased during the production of the electric field or the magnetic field.

Additionally, the apparatus for producing the electric field or the magnetic field should further include a safety device (e.g., an electric or magnetic field shielding structure, an interception device, etc.) for protecting the user from high power, when producing or intercepting the electric field or the magnetic field.

Moreover, a deviation of energy supplied is significantly large due to the on/off operation of the apparatus for producing the electric field or the magnetic field.

DISCLOSURE Technical Problem

An object of the present invention is to provide a supercooling apparatus and method which can reliably prevent the formation of ice crystal nucleuses in a stored object of a supercooled state.

Another object of the present invention is to provide a supercooling apparatus and method which can easily prevent the formation of ice crystal nucleuses and adjust a supercooling temperature of a stored object.

A further object of the present invention is to provide a supercooling apparatus and method which can maintain a stored object in a supercooled state only by the power supply in a space where only the cooling is performed.

A still further object of the present invention is to provide a supercooling apparatus and method which can reduce a temperature deviation of a stored object of a supercooled state to stably maintain the supercooled state.

A still further object of the present invention is to provide a supercooling apparatus and method which can accurately rapidly determine a supercooled state of a stored object.

A still further object of the present invention is to provide a supercooling apparatus and method which can maintain and control a supercooled state through the supply of energy with a greatly-reduced deviation, when controlling the temperature of a stored object during the cooling.

Technical Solution

According to an aspect of the present invention, there is provided a supercooling apparatus, including: a storage room provided in a storing unit where the cooling is performed and having a storing space therein to store an object; a heat source supply unit provided in the storage room and supplying heat to the storing space or generating heat in the storing space; a temperature sensing unit sensing the temperature of the storing space or the stored object; and a control unit operating the heat source supply unit based on the temperature sensed by the temperature sensing unit to enable an upper portion of the storing space to have a temperature higher than a temperature of the maximum ice crystal formation zone, such that the storing space or the stored object is maintained in a supercooled state at a temperature below the maximum ice crystal formation zone, the control unit supplying or generating heat over a given magnitude during the supercooled-state control.

In addition, preferably, the control unit maintains the upper temperature of the storing space over the phase transition temperature.

Moreover, preferably, the control unit maintains the lower temperature of the storing space or the temperature of the stored object at a preset supercooling temperature to store the stored object in the supercooled state.

Further, preferably, the control unit controls the heat source supply unit to supply or generate heat of a given magnitude range.

Furthermore, preferably, the heat source supply unit comprises first and second heat source supply units independently respectively provided on two or more surfaces of the storing space.

Still furthermore, preferably, the first or second heat source supply unit comprises two or more sub-heat source supply units, wherein at least one sub-heat source supply unit has the on state and the other one sub-heat source supply unit alternately has the on state and the off state during the supercooled-state control.

Still furthermore, preferably, the first or second heat source supply unit receives a voltage included in a voltage variable region higher than 0 V and maintains the on state to keep the stored object in the supercooled state.

Still furthermore, preferably, the temperature sensing unit includes one or more temperature sensors mounted on or adjacent to the surface having the heat source supply unit thereon.

Still furthermore, preferably, the control unit independently controls the heat source supply unit based on the temperature of the temperature sensor mounted on the same surface as the heat source supply unit or the temperature sensor mounted in the proximity of the heat source supply unit.

Still furthermore, preferably, the control unit determines whether the supercooled state of the stored object has been released according to a change in the sensed temperature from the temperature sensing unit.

According to another aspect of the present invention, there is provided a supercooling method for a cooling apparatus including a storage room which is provided in a storing unit where the cooling is performed and which has a storing space therein to store an object, the supercooling method including: cooling the stored object or the storage room to a temperature of the maximum ice crystal formation zone or a lower temperature; and supplying heat to the storing space or generating heat in the storing space, wherein the supercooling method performs sensing the temperature of the storing space or the stored object, and performs the supercooled-state control which controls at least one of the cooling and the supplying of heat based on the sensed temperature to enable an upper portion of the storing space to have a temperature higher than a temperature of the maximum ice crystal formation zone, such that the storing space or the stored object is maintained in a supercooled state at a temperature below the maximum ice crystal formation zone.

Advantageous Effects

An embodiment of the present invention can stably maintain a stored object in a supercooled state for an extended period of time by reliably preventing the formation of ice crystal nucleuses in the stored object of the supercooled state.

An embodiment of the present invention can store and maintain a stored object in a desired state by easily preventing the formation of ice crystal nucleuses and adjusting a supercooling temperature of the stored object.

An embodiment of the present invention can achieve a simple structure and independent control by maintaining a stored object in a supercooled state only by the power supply in a space where only the cooling is performed.

An embodiment of the present invention can stably maintain a supercooled state by reducing a temperature deviation of a stored object of the supercooled state.

An embodiment of the present invention can stably maintain quality of a stored object by accurately rapidly determining a supercooled state of the stored object.

An embodiment of the present invention can stably maintain a state of a stored object by maintaining and controlling a supercooled state through the supply of energy with a greatly-reduced deviation, when controlling the temperature of the stored object during the cooling.

DESCRIPTION OF DRAWINGS

FIG. 1 is a view of an example of a conventional thawing and freshness-keeping apparatus.

FIG. 2 is a circuit view of the circuit configuration of a high voltage generator.

FIG. 3 is a view showing a process in which ice crystal nucleuses are formed in a liquid during the cooling.

FIG. 4 is a view showing a process of preventing the ice crystal nucleus formation, which is applied to a supercooling apparatus according to the present invention.

FIG. 5 is a schematic configuration view of the supercooling apparatus according to the present invention.

FIG. 6 is a graph showing a supercooled state of water in the supercooling apparatus of FIG. 5.

FIG. 7 is a block diagram of a supercooling system adopting a supercooling apparatus according to the present invention.

FIG. 8 is a block diagram of a first embodiment of the supercooling apparatus of FIG. 7.

FIG. 9 is a view showing the arrangement of a heat source supply unit of the supercooling apparatus of FIG. 8.

FIG. 10 is a flowchart of a supercooling method using the supercooling apparatus of FIG. 8.

FIG. 11 is a block diagram of a second embodiment of the supercooling apparatus of FIG. 7.

FIG. 12 is a graph showing a voltage applied to a heat source supply unit in the supercooling apparatus of FIG. 11.

FIG. 13 is a flowchart of a supercooling method using the supercooling apparatus of FIG. 11.

FIG. 14 is a graph showing a temperature change caused by the on/off operation of the heat source supply unit.

FIG. 15 is a graph showing the temperature in the supercooling release of a stored object in the heat supply of FIG. 14.

FIG. 16 is a graph showing differential values of the sensed temperature of FIG. 15.

FIG. 17 is a graph showing a temperature change in the supercooling methods of FIGS. 8 and 11.

FIG. 18 is a graph showing the temperature in the supercooling release of a stored object in the heat supply of FIG. 17.

FIG. 19 is a graph showing differential values of the sensed temperature of FIG. 18.

MODE FOR INVENTION

Hereinafter, the present invention will be described in detail with reference to the exemplary embodiments and the accompanying drawings.

FIG. 3 is a view showing a process in which ice crystal nucleuses are formed in a liquid during the cooling. As illustrated in FIG. 3, a container C containing a liquid L (or a stored object) is cooled in a storing unit S with a cooling space therein.

For example, it is assumed that a cooling temperature of the cooling space is lowered from a normal temperature to a temperature below 0° C. (the phase transition temperature of water) or a temperature below the phase transition temperature of the liquid L. While the cooling is carried out, it is intended to maintain a supercooled state of the water or the liquid L (or the stored object) at a temperature below the maximum ice crystal formation zone (−1° C. to −7° C.) of the water in which the formation of ice crystals is maximized, or at a cooling temperature below the maximum ice crystal formation zone of the liquid L.

The liquid L is evaporated during the cooling such that vapor W1 is introduced into a gas Lg (or a space) in the container C. In a case where the container C is closed, the gas Lg may be supersaturated due to the evaporated vapor W1.

When the cooling temperature reaches or exceeds a temperature of the maximum ice crystal formation zone of the liquid L, the vapor W1 forms ice crystal nucleuses F1 in the gas Lg or ice crystal nucleuses F2 on an inner wall of the container C.

Alternatively, the condensation occurs in a contact portion of the surface Ls of the liquid L and the inner wall of the container C (almost the same as the cooling temperature of the cooling space) such that the condensed liquid L may form ice crystal nucleuses F3 which are ice crystals.

For example, when the ice crystal nucleuses F1 in the gas Lg are lowered and infiltrated into the liquid L through the surface Ls of the liquid L, the liquid L is released from the supercooled state and caused to be frozen. That is, the supercooling of the liquid L is released.

Alternatively, as the ice crystal nucleuses F3 are brought into contact with the surface Ls of the liquid L, the liquid L is released from the supercooled state and caused to be frozen.

As described above, according to the process of forming the ice crystal nucleuses F1 to F3, when the liquid L is stored at a temperature below its maximum ice crystal formation zone, the liquid L is released from the supercooled state due to the freezing of the vapor evaporated from the liquid L and existing on the surface Ls of the liquid L and the freezing of the vapor on the inner wall of the container C adjacent to the surface Ls of the liquid L.

FIG. 4 is a view showing a process of preventing the ice crystal nucleus formation, which is applied to a supercooling apparatus according to the present invention.

In FIG. 4, to prevent the freezing of the vapor W1 in the gas Lg, i.e., to continuously maintain the vapor W1 state, energy is applied to at least the gas Lg or the surface Ls of the liquid L so that the temperature of the gas Lg or the surface Ls of the liquid L can be higher than a temperature of the maximum ice crystal formation zone of the liquid L, more preferably, the phase transition temperature of the liquid L. In addition, to prevent the freezing although the surface Ls of the liquid L is brought into contact with the inner wall of the container C, the temperature of the surface Ls of the liquid L is maintained higher than a temperature of the maximum ice crystal formation zone of the liquid L, more preferably, the phase transition temperature of the liquid L.

Accordingly, the liquid L in the container C maintains the supercooled state at a temperature below its phase transition temperature or a temperature below its maximum ice crystal formation zone.

Moreover, when the cooling temperature in the storing unit S is a considerably low temperature, e.g., −20° C., although energy is applied to an upper portion of the container C, the liquid L which is the stored object may not be able to maintain the supercooled state. There is a need that energy should be applied to a lower portion of the container C to some extent. When the energy applied to the upper portion of the container C is relatively larger than the energy applied to the lower portion of the container C, the temperature of the upper portion of the container C can be maintained higher than the phase transition temperature or a temperature of the maximum ice crystal formation zone. Further, the temperature of the liquid L in the supercooled state can be adjusted by the energy applied to the lower portion of the container C and the energy applied to the upper portion of the container C.

The liquid L has been described as an example with reference to FIGS. 3 and 4. In the case of a stored object containing a liquid, when the liquid in the stored object is continuously supercooled, the stored object can be kept fresh for an extended period of time. The stored object can be maintained in a supercooled state at a temperature below the phase transition temperature via the above process. Here, the stored object may include meat, vegetable, fruit and other food as well as the liquid.

Furthermore, the energy adopted in the present invention may be thermal energy, electric or magnetic energy, ultrasonic-wave energy, light energy, and so on.

FIG. 5 is a schematic configuration view of the supercooling apparatus according to the present invention.

The supercooling apparatus of FIG. 5 includes a case Sr mounted in the storing unit S in which the cooling is performed and having a storing space therein, a heat generation coil H1 mounted on the inside of the top surface of the case Sr and generating heat, a temperature sensor C1 sensing a temperature of an upper portion of the storing space, a heat generation coil H2 mounted on the inside of the bottom surface of the case Sr and generating heat, and a temperature sensor C2 sensing a temperature of the lower portion of the storing space or a temperature of a stored object P.

The supercooling apparatus is installed in the storing unit S such that the cooling is performed therein. The temperature sensors C1 and C2 sense the temperature and the heat generation coils H1 and H2 are turned on to supply heat from the upper and lower portions of the storing space to the storing space. The heat supply quantity is adjusted to control the temperature of the upper portion of the storing space (or the air on the stored object P) to be higher than a temperature of the maximum ice crystal formation zone, more preferably, the phase transition temperature.

The positions of the heat generation coils H1 and H2 in FIG. 5 are appropriately determined to supply the heat (or energy) to the stored object P and the storing space. The heat generation coils H1 and H2 may be inserted into the side surfaces of the case Sr.

In addition, the storing space may be opened and closed by a drawer, etc.

FIG. 6 is a graph showing the supercooled state of water in the supercooling apparatus of FIG. 5. The graph of FIG. 6 is a temperature graph when the liquid L is water and the principle of FIGS. 4 and 5 is applied thereto.

As illustrated in FIG. 6, line I represents a curve of the cooling temperature of the cooling space, line II represents a curve of the temperature of the gas Lg (air) on the surface of the water in the container C or the case Sr (or the temperature of the upper portion of the container C or the case Sr), and line III represents a curve of the temperature of the lower portion of the container C or the case Sr. A temperature of an outer surface of the container C or the case Sr is substantially identical to the temperature of the water in the container C or the case Sr.

As shown, in a case where the cooling temperature is maintained at about −19° C. to −20° C. (see line I), when the temperature of the gas Lg on the surface of the water in the container C is maintained at about 4° C. to 6° C. which is higher than a temperature of the maximum ice crystal formation zone of the water, the temperature of the water in the container C is maintained at about −11° C. which is lower than a temperature of the maximum ice crystal formation zone of the water, but the water is stably maintained in a supercooled state which is a liquid state for an extended period of time. Here, the heat generation coils H1 and H2 supply heat.

Additionally, in FIG. 6, energy is applied to the surface of the water or the gas Lg on the surface of the water before the temperature of the water reaches a temperature of the maximum ice crystal formation zone, more preferably, the phase transition temperature due to the cooling. Thus, the water stably enters and maintains the supercooled state.

FIG. 7 is a block diagram of a supercooling system according to the present invention and FIG. 8 is a block diagram of a first embodiment of a supercooling apparatus of FIG. 7.

The supercooling system includes a cooling apparatus 100, and a supercooling apparatus 200 mounted in and cooled by the cooling apparatus 100.

The cooling apparatus 100, which is provided with a storing unit storing a stored object, includes a cooling cycle (i.e., cooling means) 110 cooling the storing unit, an input unit 120 receiving the input of a setting command or the like from a user, a display unit 130 displaying a temperature state or the like of the cooling apparatus 100, and a main control unit 140 receiving external commercial power (or another power) and controlling the cooling cycle 110 to maintain the temperature in the storing unit at a temperature below at least the maximum ice crystal formation zone.

The cooling cycle 110 is divided into indirect-cooling type and direct-cooling type according to methods for cooling the stored object.

The indirect-cooling type cooling cycle includes a compressor compressing the refrigerant, an evaporator producing the cool air to cool a storing space or a stored object, a fan making the forcible flow of the produced cool air, an inlet duct introducing the cool air into the storing space, and a discharge duct inducing the cool air passing through the storing space to the evaporator. In addition, the indirect-cooling type cooling cycle may include a condenser, a dryer, an expansion device, etc.

The direct-cooling type cooling cycle includes a compressor compressing the refrigerant, and an evaporator provided in a case defining a storing space to be adjacent to the inner surface of the case and evaporating the refrigerant. Here, the direct-cooling type cooling cycle includes a condenser, an expansion valve, etc.

The input unit, which receives the input of temperature setting of the storing unit, an operation command of the supercooling apparatus 200, function setting of a dispenser, and so on from the user, may be provided as, e.g., push buttons, a keyboard or a touch pad. For example, the operation commands of the supercooling apparatus 200 may include a freezing command, a thin-ice command, a supercooling command, etc.

The display unit 130 may display an operation basically performed by the cooling apparatus 100, e.g. the temperature of the storing unit, the cooling temperature, the operation state of the supercooling apparatus 200, etc. The display unit 130 may be implemented as an LCD display, an LED display, etc.

In this embodiment, the main control unit 140 includes a power unit 142 receiving commercial power and rectifying, smoothing and transforming the commercial power into operating power (e.g., 5 V, 12 V, etc.) necessary for the cooling apparatus 100 and the supercooling apparatus 200. The power unit 142 may be included in the main control unit 140 or provided as a separate element. The power unit 142 is connected to the supercooling apparatus 200 through a power line PL to supply the necessary operating power to the supercooling apparatus 200.

The main control unit 140 includes a microcomputer 144 controlling the cooling cycle 110, the input unit 120 and the display unit 130 to enable the cooling apparatus 100 to perform the cooling operation and maintaining the inside of the storing unit at a temperature below at least the maximum ice crystal formation zone. The main control unit 140 includes a memory (not shown) storing necessary data.

The main control unit 140 (particularly, the microcomputer 144) may be connected to the supercooling apparatus 200 through a data line DL. The main control unit 140 may receive data (e.g., the current operation state of the supercooling apparatus 200) from the supercooling apparatus 200 through the data line DL, and store the data or display the data on the display unit 130. The data line DL may be selectively provided.

The microcomputer 144 controls the temperature in the storing unit according to the temperature setting from the input unit 120, and maintains the inside of the storing unit at a temperature below at least the maximum ice crystal formation zone to independently perform the control of the supercooling apparatus 200, such as the supercooling control, thin-ice control, freezing control, etc.

As illustrated in FIG. 8, the supercooling apparatus 200, which is provided with an independent storage unit having a storing space therein to store an object and being mounted and cooled in the storing unit, includes a heat source supply unit 210 supplying heat to the storing space or generating heat in the storing space, a temperature sensing unit 220 sensing the temperature of the storing space or the stored object, an input unit 230 receiving the input of a command from the user, a display unit 240 displaying a state of the storing space or the stored object or an operation of the supercooling apparatus 200, and a sub-control unit 280 controlling the heat source supply unit 210, which is a temperature control means, based on the sensed temperature from the temperature sensing unit 220 such that the stored object in the independent storage room is stored in either a supercooled state or a frozen state.

The supercooling apparatus 200 is operated by the operating power applied from the main control unit 140. The wiring for power supply (the wiring connected to the power line PL) is connected to the entire power-needing components. This configuration has been publicly known to a person of ordinary skill in the art, and thus its description will be omitted.

The heat source supply unit 210 corresponds to a temperature control means which controls the temperature in the storing space to maintain the temperature for each of the supercooled-state control, the thin-ice control and the freezing control. The heat source supply unit 210, which is a means for applying energy to the storing space, may produce thermal energy, electric or magnetic energy, ultrasonic-wave energy, light energy, microwave energy, etc. and apply such energy to the storing space. Moreover, the heat source supply unit 210 may supply energy to thaw the stored object, when it is frozen.

The heat source supply unit 210 is composed of a plurality of sub-heat source supply units and mounted on an upper or lower portion or a side surface of the storing space to supply energy to the storing space. In this embodiment, the heat source supply unit 210 includes an upper heat source supply unit 210 a formed in the upper side of the independent storage room which is the upper side of the storing space, and a lower heat source supply unit 210 b formed in the lower side of the independent storage room which is the lower side of the storing space. The upper heat source supply unit 210 a and the lower heat source supply unit 210 b may be independently or integrally controlled by the sub-control unit 280.

Further, the upper heat source supply unit 210 a includes a sub-heat source supply unit Hon1 which always supplies or generates heat, while the supercooling apparatus 200 performs the supercooling control, and a sub-heat source supply unit H1 which is on/off-operated by the on/off control of the sub-control unit 280. The lower heat source supply unit 210 b includes a sub-heat source supply unit Hon2 which always supplies or generates heat, while the supercooling apparatus 200 performs the supercooling control, and a sub-heat source supply unit H2 which is on/off-operated by the on/off control of the sub-control unit 280.

Although the sub-heat source supply units Hon1 and Hon2 are controlled in the on state by the sub-control unit 280, they may receive a pulse-type control signal such as a PWM signal and alternately have the on state and the off state. However, it should be appreciated that the sub-heat source supply units Hon1 and Hon2 maintain the on state by a duty ratio even in this pulse control method. In addition, the sub-heat source supply units Hon1 and Hon2 may always receive an on-state signal.

Therefore, the heat source supply unit 210 uses the sub-heat source supply units Hon1 and Hon2 to supply or generate heat over a given quantity during the supercooling control.

Moreover, the sub-control unit 280 may control the sub-heat source supply units H1 and H2 to further supply necessary heat according to the sensed temperature from the temperature sensing unit 220. The supercooling apparatus 200 supplies or generates minimum heat through the sub-heat source supply units Hon1 and Hon2 and maximum heat through the on-control of the entire heat source supply units 210 a and 210 b. In other words, the supercooling apparatus 200 supplies or generates heat of a given range greater than ‘0’.

Further, the temperature sensing unit 220, which senses the temperature of the storing space or the temperature of the stored object, corresponds to a sensor provided on a sidewall of the storing space to sense the temperature of the air in the storing space or provided in proximity or contact with the stored object to accurately sense the temperature of the stored object. The temperature sensing unit 220 applies a change value of a current value, a voltage value or a resistance value corresponding to the temperature to the sub-control unit 280. The temperature sensing unit 220 senses a sudden rise in the temperature of the stored object or the storing space during the phase transition of the stored object and enables the sub-control unit 280 to recognize the release of the supercooled state of the stored object. In this embodiment, the temperature sensing unit 220 may be composed of an upper sensing unit 220 a formed in the upper side of the independent storage room which is the upper side of the storing space, and a lower sensing unit 220 b formed in the lower side of the independent storage room which is the lower side of the storing space. The upper sensing unit 220 a and the lower sensing unit 220 b are mounted on or adjacent to the surfaces having the upper heat source supply unit 210 a and the lower heat source supply unit 210 b thereon.

The sub-control unit 280 may control the heat source supply unit 210 to selectively perform the freezing control, the thin-ice control and the supercooling control according to the sensed temperature from the temperature sensing unit 220. Particularly, the sub-control unit 280 may control the upper heat source supply unit 210 a according to the sensed temperature from the upper sensing unit 220 a and the lower heat source supply unit 210 b according to the sensed temperature from the lower sensing unit 220 b, respectively.

The input unit 230, which enables the user to select an on/off switch function of the supercooling apparatus 200, a freezing control command, a thin-ice control command and a supercooling control command, may be provided as, e.g., push buttons, a keyboard or a touch pad.

The display unit 240, which displays the on/off state of the supercooling apparatus 200 and the current control thereof (e.g., the freezing control, the thin-ice control and the supercooling control), may be provided as an LCD display, an LED display, etc.

As described above, the sub-control unit 280 may control the heat source supply unit 210 according to the sensed temperature from the temperature sensing unit 220, thereby independently performing the freezing control, the thin-ice control and the supercooling control with respect to the main control unit 140 and the cooling apparatus 100. For this independent control, the sub-control unit 280 may include a memory storing a control algorithm, etc.

Here, in the freezing control, the heat source supply unit 210 does not or seldom supplies or generates heat such that the stored object in the independent storage room is frozen. This control may be performed by turning off the supercooling apparatus 200. In the freezing control, since the temperature is maintained almost same as the cooling temperature of the cooling apparatus 100, it becomes a temperature below at least the maximum ice crystal formation zone, e.g., −20° C.

In the supercooling control, the temperature of the stored object ranges from, e.g., −3° C. to −4° C. and the stored object is stored in the supercooled state. The control which senses the freezing of the stored object of the supercooled state by the phenomenon that the temperature of the stored object suddenly rises from, e.g., −4° C. is further performed during the supercooling control. Furthermore, the control which performs the thawing through the operation of the heat source supply unit 210 and resumes the cooling after the completion of the thawing is performed in the release of the supercooled state.

Particularly, the sub-control unit 280 controls the heat source supply unit 210 to supply or generate heat of a given range greater than ‘0’ in the storing space and the stored object during the supercooling control.

In the thin-ice control, the temperature of the stored object is controlled to be lower than the temperature in the supercooling control and higher than the cooling temperature of the cooling apparatus 100 using the heat source supply unit 210, such that the stored object is stored in a sub-frozen state, taken out and easily cut by a knife, etc.

The sub-control unit 280 may intercept the power supply to the respective elements according to the on/off switch input of the supercooling apparatus 200 from the input unit 230, thereby preventing their operation.

In addition, the sub-control unit 280 may receive three or more control commands from the input unit 230 as described above and perform the corresponding operations.

The input unit 230 further has a function of acquiring a thawing command, and the sub-control unit 280 operates the heat source supply unit 210 to apply energy (particularly, heat energy) to thaw the stored object according to the thawing command from the input unit 230.

FIG. 9 is a view showing the arrangement of the heat source supply unit of the supercooling apparatus of FIG. 8. Unlike the heat source supply unit of FIG. 5, in the heat source supply unit of FIG. 9, the sub-heat source supply units Hon1 and Hon2 always maintaining the on state are formed on the upper and lower sides of the independent storage room, respectively, and supply or generate heat over a given magnitude in the storing space.

FIG. 10 is a flowchart of a supercooling method using the supercooling apparatus of FIG. 8.

At step S51, the cooling apparatus 100 performs the cooling, and an object is received and cooled in the independent storage room of the supercooling apparatus 200.

At step S53, when the current control to be performed is the supercooling control, the sub-control unit 280 of the supercooling apparatus 200 operates the sub-heat source supply units Hon1 and Hon2 (overall, Hon) of the heat source supply unit 210 to continuously supply energy (i.e., heat) over a given quantity to the storing space or the stored object.

At step S55, the sub-control unit 280 acquires the sensed temperature from the temperature sensing unit 220. More specifically, the sub-control unit 280 acquires the sensed temperatures from the upper sensing unit 220 a and the lower sensing unit 220 b, respectively.

At step S57, the sub-control unit 280 determines whether heat is further needed according to the sensed temperatures from the upper sensing unit 220 a and the lower sensing unit 220 b, respectively. For example, if the temperature from the upper sensing unit 220 a is lower than the phase transition temperature, or if the temperature from the lower sensing unit 220 b is lower than a preset supercooling temperature (e.g., −3° C.), the sub-control unit 280 goes to step S59, and if not, the sub-control unit 280 goes to step S61.

At step S59, the sub-control unit 280 independently respectively controls the sub-heat source supply units H1 and H2 (overall, H) in the on state according to the heat-needing position, thereby supplying heat.

At step S61, the sub-control unit 280 switches the sub-heat source supply units H1 and H2 to the off state, or maintains the sub-heat source supply units H1 and H2 in the off state when they are currently in the off state.

The steps S59 and S61 lead to the step S55 such that the sub-control unit 280 continuously maintains the stored object in the supercooled state.

Moreover, the supercooling method of FIG. 10 further includes a process of determining whether the stored object has been frozen. If the stored object has been frozen, the thawing process may be performed as described above.

FIG. 11 is a block diagram of a second embodiment of the supercooling apparatus of FIG. 7.

The supercooling apparatus 200 a of FIG. 11 is similar to the supercooling apparatus 200 a of FIG. 8 except voltage changing units 250 a and 250 b, a heat source supply unit 211, and a sub-control unit 280 a.

The voltage changing units 250 a and 250 b change a magnitude of an operating voltage applied to the heat source supply unit 211 (including an upper heat source supply unit 211 a and a lower heat source supply unit 211 b by the control of the sub-control unit 280 a, and thus substantially changes heat supplied by the heat source supply unit 211. For example, the magnitude of the operating voltage may be set between 3 V and 10 V. For example, the voltage changing units 250 a and 250 b may be implemented as variable resistors, transformers, etc.

Unlike the heat source supply unit 210 of FIG. 8, the upper heat source supply unit 211 a and the lower heat source supply unit 211 b include only sub-heat source supply units Hon1 and Hon2, and thus always maintain the on state. However, it should be appreciated that the magnitude of the voltage applied thereto by the voltage changing units 250 a and 250 b is changed. That is, the supercooling apparatus 200 a of FIG. 11 does not include a heat source supply unit controlled in the on/off state like the sub-heat source supply units H1 and H2 of the supercooling apparatus of FIG. 9.

The sub-control unit 280 a individually controls the voltage changing units 250 a and 250 b according to an upper sensed temperature and a lower sensed temperature from a temperature sensing unit 220 during the supercooling control, thereby applying a minimum voltage higher than at least 0 V to the heat source supply unit 211. If the heat supply is further required according to the current sensed temperature, the voltage applied is changed within a given range.

FIG. 12 is a graph showing the voltage applied to the heat source supply unit in the supercooling apparatus of FIG. 11. As illustrated in FIG. 12, the range of the voltage applied to the upper and lower heat source supply units 211 a and 211 b by the voltage changing units 250 a and 250 b ranges from 3 V to 10 V. A voltage equal to or higher than 3 V is always applied to generate or supply heat over a given quantity.

FIG. 13 is a flowchart of a supercooling method using the supercooling apparatus of FIG. 11.

This flowchart provides a case where the range of the variable voltage includes only two stages, i.e., a first voltage which is the lowest voltage and a second voltage which is the highest voltage.

At step S71, the cooling apparatus 100 performs the cooling, and an object is stored and cooled in the independent storage room of the supercooling apparatus 200 a.

At step S73, when the current control to be performed is the supercooling control, the sub-control unit 280 a of the supercooling apparatus 200 a applies the first voltage which is the lowest voltage to the heat source supply unit 211 through the voltage changing units 250 a and 250 b.

At step S75, the sub-control unit 280 a acquires the sensed temperature from the temperature sensing unit 220. More specifically, the sub-control unit 280 a acquires sensed temperatures from an upper sensing unit 220 a and a lower sensing unit 220 b, respectively.

At step S77, the sub-control unit 280 a determines whether heat is further needed according to the sensed temperatures from the upper sensing unit 220 a and the lower sensing unit 220 b, respectively. For example, if the temperature from the upper sensing unit 220 a is lower than the phase transition temperature, or if the temperature from the lower sensing unit 220 b is lower than a preset supercooling temperature (e.g., −3° C.), the sub-control unit 280 a goes to step S79, and if not, the sub-control unit 280 a goes to step S81.

At step S79, the sub-control unit 280 a independently controls the voltage changing units 250 a and 250 b according to the heat-needing position, and thus applies the second voltage to the upper heat source supply unit 211 a or the lower heat source supply unit 211 b, thereby supplying heat.

At step S81, the sub-control unit 280 a controls the voltage changing units 250 a and 250 b to change the magnitude of the voltage to the first voltage or apply the same first voltage to the upper heat source supply unit 211 a or the lower heat source supply unit 211 b, thereby supplying heat.

The steps S79 and S81 lead to the step S75 such that the sub-control unit 280 a continuously maintains the stored object in the supercooled state.

Moreover, the supercooling method of FIG. 13 further includes a process of determining whether the stored object has been frozen. If the stored object has been frozen, the thawing process may be performed as described above.

FIG. 14 is a graph showing a temperature change caused by the on/off operation of the heat source supply unit. In the supercooling apparatus of FIG. 5 where heat is supplied to or generated in the stored object by the on/off operation of the heat source supply units H1 and H2, as shown in a temperature graph I on the upper side of FIG. 14, the temperature of the storing space (the temperature sensed by the temperature sensor C1) is significantly changed by the on operation and the off operation of the heat source supply units H1 and H2. As shown in the lower side of FIG. 14, both the heat source supply units H1 and H2 have the on state or the off state. Therefore, as known from the temperature graph I, a deviation of heat applied to or generated in the storing space is great.

FIG. 15 is a graph showing the temperature in the supercooling release of the stored object in the heat supply of FIG. 14. In FIG. 15, a sensed temperature graph II represents the temperature sensed by the temperature sensor C2 and a temperature graph III represents the actual temperature of the stored object. A temperature deviation is significant due to the influence of the on/off operation of the heat source supply units H1 and H2. Particularly, in a supercooling release time Tsc when the supercooling of the stored object is released and the temperature thereof is raised, the sensed temperature is more or less changed but almost in the previous change pattern. Here, the sensed temperature is lower than the temperature of the stored object. As illustrated in FIG. 15, although the stored object is released from the supercooled state, in the case of meat, the stored object may be frozen without reaching the phase transition temperature.

FIG. 16 is a graph showing differential values of the sensed temperature of FIG. 15. A curve A represents the distribution of primary differential values of the sensed temperature and a curve B represents the distribution of secondary differential values of the sensed temperature. The curves A and B have extremely similar change patterns, and thus considerably overlap with each other.

Particularly, the curves A and B are changed with smaller peak values than the previous ones in the supercooling release time Tsc. However, such changes are included in the previous peak-peak values. Accordingly, the supercooling apparatus cannot easily determine whether the peak value in the supercooling release time Tsc results from the change in the peak value caused by the supercooling release.

FIG. 17 is a graph showing a temperature change in the supercooling methods of FIGS. 8 and 11. A minimum quantity Q1 of heat and a maximum quantity Qall of heat are applied to or generated in the storing space or the stored object by the heat source supply units 210 a and 210 b and 211 a and 211 b. A change width of the heat quantity is small, and thus a change width of a temperature graph I representing the temperature sensed by the upper sensing unit 220 a is small.

FIG. 18 is a graph showing the temperature in the supercooling release of the stored object in the heat supply of FIG. 17. As illustrated in FIG. 18, a sensed temperature graph II representing the temperature sensed by the lower sensing unit 220 b has a small deviation, and a temperature graph III representing the temperature of the stored object has a temperature change almost equivalent to the sensed temperature graph II. Particularly, although the temperature of the stored object is suddenly raised in a supercooling release time Tsc, the temperature sensed by the lower sensing unit 220 b continuously maintains a relatively small deviation pattern.

FIG. 19 is a graph showing differential values of the sensed temperature of FIG. 18. A curve A represents the distribution of primary differential values of the sensed temperature and a curve B represents the distribution of secondary differential values of the sensed temperature. The curves A and B have extremely similar change patterns, and thus considerably overlap with each other.

Particularly, the curves A and B are changed with peak values much larger than the previous ones in the supercooling release time Tsc. Such changes are significantly larger than the previous peak-peak values. Therefore, when the peak value in the supercooling release time Tsc has a differential value moving out of differential determination values +D and −D for the supercooling release, the supercooling apparatus can accurately determine that the supercooling of the stored object has been released.

The present invention has been described in detail in connection with the exemplary embodiments and the accompanying drawings. However, the scope of the present invention is not limited thereto but is defined by the appended claims. 

1. A supercooling apparatus, comprising: a storage room provided in a storing unit where the cooling is performed and having a storing space therein to store an object; a heat source supply unit provided in the storage room and supplying heat to the storing space or generating heat in the storing space; a temperature sensing unit sensing the temperature of the storing space or the stored object; and a control unit operating the heat source supply unit based on the temperature sensed by the temperature sensing unit to enable an upper portion of the storing space to have a temperature higher than a temperature of the maximum ice crystal formation zone, such that the storing space or the stored object is maintained in a supercooled state at a temperature below the maximum ice crystal formation zone, the control unit supplying or generating heat over a given magnitude during the supercooled-state control.
 2. The supercooling apparatus of claim 1, wherein the control unit maintains the upper temperature of the storing space over the phase transition temperature.
 3. The supercooling apparatus of claim 1, wherein the control unit maintains the lower temperature of the storing space or the temperature of the stored object at a preset supercooling temperature to store the stored object in the supercooled state.
 4. The supercooling apparatus of claim 1, wherein the control unit controls the heat source supply unit to supply or generate heat of a given magnitude range.
 5. The supercooling apparatus of claim 4, wherein the heat source supply unit comprises first and second heat source supply units independently respectively provided on two or more surfaces of the storing space.
 6. The supercooling apparatus of claim 5, wherein the first or second heat source supply unit comprises two or more sub-heat source supply units, wherein at least one sub-heat source supply unit has the on state and the other one sub-heat source supply unit alternately has the on state and the off state during the supercooled-state control.
 7. The supercooling apparatus of claim 5, wherein the first or second heat source supply unit receives a voltage included in a voltage variable region higher than 0 V and maintains the on state to keep the stored object in the supercooled state.
 8. The supercooling apparatus of claim 5, wherein the temperature sensing unit comprises one or more temperature sensors mounted on or adjacent to the surface having the heat source supply unit thereon.
 9. The supercooling apparatus of claim 8, wherein the control unit independently controls the heat source supply unit based on the temperature of the temperature sensor mounted on the same surface as the heat source supply unit or the temperature sensor mounted in the proximity of the heat source supply unit.
 10. The supercooling apparatus of claim 4, wherein the control unit determines whether the supercooled state of the stored object has been released according to a change in the sensed temperature from the temperature sensing unit.
 11. A supercooling method for a cooling apparatus including a storage room which is provided in a storing unit where the cooling is performed and which has a storing space therein to store an object, the supercooling method comprising: cooling the stored object or the storage room to a temperature of the maximum ice crystal formation zone or a lower temperature; and supplying heat to the storing space or generating heat in the storing space, wherein the supercooling method performs sensing the temperature of the storing space or the stored object, and performs the supercooled-state control which controls at least one of the cooling and the supplying of heat based on the sensed temperature to enable an upper portion of the storing space to have a temperature higher than a temperature of the maximum ice crystal formation zone, such that the storing space or the stored object is maintained in a supercooled state at a temperature below the maximum ice crystal formation zone.
 12. The supercooling method of claim 11, wherein the supplying of heat is to supply or generate heat over a given magnitude during the supercooled-state control.
 13. The supercooling method of claim 11, wherein the supercooled-state control is to maintain the upper temperature of the storing space over the phase transition temperature.
 14. The supercooling method of claim 11, wherein the supercooled-state control is to maintain the lower temperature of the storing space or the temperature of the stored object at a preset supercooling temperature to store the stored object in the supercooled state.
 15. The supercooling method of claim 11, wherein the supplying of heat is to supply or generate heat of a given magnitude range.
 16. The supercooling method of claim 15, wherein the supplying of heat is performed by first and second heat source supply units provided in different locations, and the supplying of heat is to perform first lower heat supply which maintains the first heat source supply unit in the on state and second lower heat supply which maintains the second heat source supply unit alternately in the on state and the off state at the same time during the supercooled-state control.
 17. The supercooling method of claim 11, comprising determining, at a control unit, whether the supercooled state of the stored object has been released according to a change in the sensed temperature from a temperature sensing unit. 